Field of the Invention
The present invention relates to a video providing apparatus.
When a viewer has a disease in a part of the retina, an external light introduced into a disease portion out of external light projected onto the retina by the crystalline lens of the eyeball is not perceived, so that video in a portion, corresponding to the disease portion, in view seems as if it were missing, for example. Particularly when the disease portion exists at the center of the retina, a large part of an important portion of information from the external world is lost. When a viewer has a disease in the light transmittance of the crystalline lens, a pupil (hole) is artificially formed outside the crystalline lens. Even by the artificial pupil, however, the viewer cannot see clear video. When a viewer has a disease in the focus accommodation function of the crystalline lens, the viewer wears glasses. However, it is difficult for a lens in a pair of glasses to correspond to a bifocal without being divided into regions. When the focusing function of the crystalline lens is lost, the external light cannot be formed on the retina. Even if the darkness and brightness of the external world can be recognized, therefore, it is difficult to clearly recognize the video.
In view of the foregoing circumstances, an object of the present invention is to provide a video providing apparatus capable of giving clear video to a patient with an eye disease.
A video providing apparatus according to the present invention is characterized by comprising a light source comprising a light emitter for emitting non-oscillation natural emission light; a video producing optical system for modulating the light from the light source in an spatial light modulator and outputting video light; a convergent element for converging the video light; and a pinhole arranged at the rear focal point of the convergent element, a viewer being caused to view video by Maxwellian view.
In the above-mentioned configuration, the video produced by the spatial light modulator (e.g., video obtained by imaging the external world using a CCD (Charge Coupled Device) camera) is directly projected onto the retina without being affected by the lens function in the crystalline lens of the eyeball. Even when there is only a narrow optical path due to the artificial pupil or the corneal opacity, the video can be directly projected onto the retina. The light source comprising the light emitter for emitting the non-oscillation natural emission light is used, thereby making it possible to restrain the production of coherent noise (video noise). Further, the video providing apparatus has the pinhole. Even when the light from each of pixel portions of the spatial light modulator has a slight expanse (e.g., even in a case where an LED (Light Emitting Diode) or the like is used as a light source), a bundle of light rays is narrowed down, thereby making it possible to give a large depth of focus to recognize clear video.
A video providing apparatus according to the present invention is characterized by comprising a light source comprising a light emitter for emitting non-oscillation natural emission light; a video producing optical system for modulating the light from the light source in an spatial light modulator and outputting video light; a first convergent element for converging the video light; and an optical system comprising a pair of second convergent elements provided between the video producing optical system and the first convergent element, and a pinhole arranged at the mutual focal points of the second convergent elements, a viewer being caused to view video by Maxwellian view.
In the above-mentioned configuration, the video produced by the spatial light modulator (e.g., video obtained by imaging the external world using a CCD camera) is directly projected onto the retina without being affected by the lens function in the crystalline lens of the eyeball. Even when there is only a narrow optical path due to the artificial pupil or the corneal opacity, the video can be directly projected onto the retina. The light source comprising the light emitter for emitting the non-oscillation natural emission light is used, thereby making it possible to restrain the production of coherent noise (video noise). Further, the video providing apparatus has the pinhole. Even when the light from each of pixel portions of the spatial light modulator has a slight expanse (e.g., even in a case where an LED or the like is used as a light source), a bundle of light rays is narrowed down, thereby making it possible to give a large depth of focus to recognize clear video. Further, a conjugate points of the pinhole can be placed at the center of the pupil of the eyeball, thereby making it possible to give wider view to a patient with an eye disease, as compared with that in a configuration in which the pinhole is directly placed in front of the eyes.
It is desirable that the light source is a parallel light source for converting dispersive light into parallel light and giving the parallel light to the spatial light modulator.
The parallel light source may comprise a pinhole at the mutual focal points of a pair of convergent elements.
The pinhole in the parallel light source may be provided with light diffusion means.
A video providing apparatus according to the present invention is characterized by comprising a light source comprising a light emitter for emitting non-oscillation natural emission light; a video producing optical system for converging dispersive light from the light source to provide the convergent light to an spatial light modulator, and outputting video light in the converging state modulated by the spatial light modulator; a pinhole provided at a converging point of the video light in the converging state; and an optical element for converging the video light in the dispersive state which has passed through the pinhole and positioning the converging point at the position of the eyeball of a viewer, the viewer being caused to view video by Maxwellian view.
In the above-mentioned configuration, the video produced by the spatial light modulator (e.g., video obtained by imaging the external world using a CCD camera) is directly projected onto the retina without being affected by the lens function in the crystalline lens of the eyeball. Even when there is only a narrow optical path due to the artificial pupil or the corneal opacity, the video can be directly projected onto the retina. The light source comprising the light emitter for emitting the non-oscillation natural emission light is used, thereby making it possible to restrain the production of coherent noise (video noise). Further, the video providing apparatus has the pinhole. Even when the light from each of pixel portions of the spatial light modulator has a slight expanse (e.g., even in a case where an LED or the like is used as a light source), a bundle of light rays is narrowed down, thereby making it possible to give a large depth of focus to recognize clear video. Further, a conjugate points of the pinhole can be placed at the center of the pupil of the eyeball, thereby making it possible to give wider view to a patient with an eye disease, as compared with that in a configuration in which the pinhole is directly placed in front of the eyes. Further, the necessity of an optical system required to convert dispersive light into parallel light is eliminated, thereby making it possible to reduce the optical path length to miniaturize the video providing apparatus.
In the video providing apparatuses having the configurations, the light source may be a white light source, and the spatial light modulator may comprise respective modulators for read light, green light, and blue light.
Consequently, color video can be provided to the patient with an eye disease.